Question

Carolina Savirana Craz 3/12/20 GECC-Polymerase Chain Reaction 1. What is the purpose of the polymerase chain reaction? a. To repair damaged DNA b. To make copies of entire chromosomes c. To make copies of specific regions of DNA d. To prepare cells for cell division 2. The polymerase chain reaction is most comparable to what cellular process? a. Mitosis b. Replication c. Transcription d. Translation 3. When enzymes are elongating (building) a newly synthesized DNA strand in PCR, new nucleotides are being added to the_ of the growing strand. a. S'phosphate group b. A nitrogenous base c. 3'hydroxyl of deoxyribose d. 2'H of deoxyribose 4. PCR utilizes specific DNA primers and a polymerase enzyme to make copies of a particular DNA sequence. The primers must first attach (anneal) to separated DNA at the target sequences so that polymerase can build new DNA strands. What must also be added to the mixture besides primers and polymerase enzyme in order to get amplification of DNA? a. RNA polymerase b. dNTPs c. electron carriers d. DNA repair enzymes 5. Magnesium chloride (MgCl2) is also required for making copies of target DNA by PCR. What might be an important role of the ion Mgt in this technique? a. Act as a cofactor for polymerase b. Act as an allosteric inhibitor of polymerase C. Make the PCR solution hypertonic to the polymerase enzyme d. Allows for easy isolation of newly synthesized DNA by charge sorting

Answer 1

1) PCR uses double-stranded DNA, DNA polymerase, dNTPs and primers to amplify the DNA large number of DNA copies can be produced via PCR so the answer is c) to make copies of specific regions of DNA.

(the region between the primer binding site are amplified)

2) the DNA is replicated by the Taq polymerase by adding dNTPs complementary to the template strand, to the 3`-OH of the growing nucleic acid, so the answer is b) replication.

3) DNA polymerase can add dNTPs to the 3`-OH of the existing nucleic acid so the replication occurs in the 5 to 3` direction so the answer is c) 3`- hydroxyl of deoxyribose.

4) the DNA is replicated by the Taq polymerase by adding dNTPs complementary to the template strand, to the 3`-OH of the growing nucleic acid, so the answer is b) dNTPs.

5) Mg2+ is a cofactor of the DNA polymerase, DNA polymerase is functional only when it is bound to Mg2+ so the answer is a) act as a cofactor for polymerase.